Experimental research on emission and removal of dioxins in flue gas from a co-combustion of MSW and coal incinerator

This paper describes the experimental study of dioxins removal from flue gas from a co-combustion municipal solid waste and coal incinerator by means of a fluidized absorption tower and a fabric filter. A test rig has been set up. The flow rate of flue gas of the test rig is 150-2000 m3/h. The system was composed of a humidification and cooling system, an absorption tower, a demister, a slurry make-up tank, a desilter, a fabric filter and a measurement system. The total height of the absorption tower was 6.5m, and the diameter of the reactor pool was 1.2 m. When the absorbent was 1% limestone slurry, the recirculation ratio was 3, the jet rate was 5-15 m/s and the submerged depth of the bubbling pipe under the slurry was 0.14 m, the removal efficiency for dioxins was 99.35%. The concentration of dioxins in the treated flue gas was 0.1573 x 10(-13)kg/Nm3 and the concentration of oxygen was 11%. This concentration is comparable to the emission standards of other developed countries.     

污水污泥裂解及其性能的研究

以碘吸附值为裂解残渣吸附性能的指标,通过单因素实验和正交实验,确定了制备裂解残渣的最佳工艺条件,并对残渣的表面元素组成、孔结构组成、晶相组成和吸附性能等性质进行了表征。结果显示：以浓度均为5 mol/L的ZnCl₂和H₂SO₄作活化剂、复配比2∶1、活化温度600℃、活化时间1 h、固液比1∶2.5,制得的裂解残渣酸洗后碘值平均值可达892.8 mg/g;用制备的裂解残渣对苯酚废水进行处理,室温下振荡5 min,苯酚去除率即可达到87.9%,且符合Langmuir吸附等温线方程和Freundlich吸附等温线方程。     

Aging and compressibility of municipal solid wastes

The expansion of a municipal solid waste (MSW) landfill requires the ability to predict settlement behavior of the existing landfill. The practice of using a single compressibility value when performing a settlement analysis may lead to inaccurate predictions. This paper gives consideration to changes in the mechanical compressibility of MSW as a function of the fill age of MSW as well as the embedding depth of MSW. Borehole samples representative of various fill ages were obtained from five boreholes drilled to the bottom of the Qizhishan landfill in Suzhou, China. Thirty-one borehole samples were used to perform confined compression tests. Waste composition and volume-mass properties (i.e., unit weight, void ratio, and water content) were measured on all the samples. The test results showed that the compressible components of the MSW (i.e., organics, plastics, paper, wood and textiles) decreased with an increase in the fill age. The in situ void ratio of the MSW was shown to decrease with depth into the landfill. The compression index, Cc, was observed to decrease from 1.0 to 0.3 with depth into the landfill. Settlement analyses were performed on the existing landfill, demonstrating that the variation of MSW compressibility with fill age or depth should be taken into account in the settlement prediction.     

生活垃圾填埋场封场后种植植物中重金属迁移研究

在上海老港生活垃圾填埋场填埋单元封场的覆盖土中掺混了矿化垃圾种植植物,分析Cd、Pb、Cu、Zn 4种重金属在土壤和植物中的迁移变化,研究表明:(1)覆盖土土质从一般耕作土变成肥沃土壤;覆盖土和种植混合土重金属Cd、Pb、Cu、Zn中Cd、Pb含量相近,但种植土的Cu含量略大于覆盖原土,Zn含量远大于覆盖原土;(2)植物能富集土壤和垃圾中的重金属,木本植物的根部富集重金属的能力强于草本植物,但重金属在草本植物根、茎、叶中的迁移速度大于木本植物;(3)植物根、茎、叶的Cu、Zn含量均远大于未受污染土壤种植植物相应部位的Cu、Zn含量,种植的植物不能供家养动物食用,以免通过食物链作用危及人体安全.     

微好氧颗粒污泥工艺降解五氯酚的实验研究

微好氧颗粒污泥工艺能够同时进行好氧氧化和厌氧还原过程，是处理五氯酚（PCP）的理想方法。对影响好氧颗粒污泥降解PCP的因素水力学上升流速、碱加入量以及水力停留时间进行考察。结果表明，水力学上升流速为4.58m／h，进水NaHCO3浓度为900mg／L，水力停留时间为24h时，处理效果比较好。     

Solventless sample preparation for pesticides analysis in environmental water samples using solid-phase microextraction-high resolution gas chromatography/mass spectrometry (SPME-HRGC/MS)

Solid-phase micro-extraction (SPME) coupled on line with high resolution gas chromatography and mass spectrometric detection is described for the analysis of pesticides in environmental water samples. Experiments were performed in order to optimize the SPME extraction conditions for selected pesticides including tiomethon, trichorfon, dimethoate, diazinon, malathion, dicofol, methidathion, ethion, bromopropylate and pyrazophos from spiked water solutions. To enhance the SPME efficiency, experimental conditions including the fiber composition, stirring rate, temperature, adsorption time, desorption time and salt concentration were optimized. After validation, the SPME-GC/MS methodology was applied to real-world environmental water samples.     

Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments

The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography–mass spectrometry (GC–MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC–MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment.     

Characteristics of organic precursors and their relationship with disinfection by-products

The molecular weight distribution and chemical composition of precursors and their relationship with disinfection by-products (DBPs) were investigated. Most of the organic matter responsible for the major DBP precursors in the Pan-Hsin water are small compounds with a molecular weight less than 1 kDa. The hydrophobic acids display the greatest ability to produce DBP. Therefore, effective removal of small molecules or hydrophobic acidic organics prior to disinfection process will significantly reduce the DBP concentration in the finished water. Although the coagulation process is effective in removing large organic precursors and the removal efficiencies of CHCl3 formation potential and organic carbon increase proportionally to the molecular weight of the precursors, the conventional treatment methods have limited efficiency in eliminating small precursors, which have high DBP formation potential.     

饮用水中典型致嗅物质吹扫捕集-气相色谱质谱检测方法及优化

采用吹扫捕集/气相色谱-质谱（GC-MS）法对饮用水中致嗅物质2-甲基异茨醇（2-MIB）和土臭素（GSM）进行测定。通过调整吹扫温度、吹扫时间、吹扫时捕集阱的温度、六通阀温度和传输管线温度,分析吹扫捕集条件对吹扫捕集效率的影响,并确定最佳吹扫捕集条件。2-MIB和GSM的方法检出限（MDL）分别为0.729 ng·L-1和1.037 ng·L-1,方法定量限（MQL）分别为2.187 ng·L-1和3.112 ng·L-1,平均加标回收率分别在92%~108%和88%~104%范围内,相对标准偏差分别小于6.5%和9.0%.在20~300 ng·L-1的范围内,各异嗅化合物浓度与响应值的线性关系均良好,相关系数均大于0.999。该方法具有操作简便、检出限低,相关性良好、灵敏度高、重复性好等优点。     

可张孔曝气器曝气能耗试验研究

通过试验研究,总结出可张孔曝气阻力损失的影响因素,以优化产品的结构设计参数,降低产品在工程应用中的能耗,获取更好的经济效益。